Below liquid manways (BLMs) exist that are used as access points for tanks or containers. For example, BLMs exist that are used in fermentation and storage tanks as access points to empty and/or clean bottoms of the tanks. These types of BLMs provide liquid-tight seals, and contain head pressures from vertical columns of liquid contained in the tanks.
A typical BLM has a hinged door, swing bolts, and a seal. Because this type of BLM has hinges pivotably fixing the door to the tank, it is difficult to manage a flow rate of product emptying out of the tank. Moreover, the BLM has hinges pivotably fixing the door to the tank, the interface between the BLM and the tank creates interferences (e.g., lips, walls, bridges) across the opening of the BLM. Thus, the BLM impedes the flow of product emptying from the tank and/or builds up (e.g., bridges) product across the opening of the BLM, making the removal and/or cleaning of the product from the bottom of the tank more labor intensive, time consuming, and costly. While, existing BLMs may provide liquid tight seals for containing products in tanks, they are unable to manage flow rates of products emptying out of the tanks, and impede the flow of products emptying from the tanks, which make them more labor intensive, time consuming, and costly.
Sliding gate BLMs also exist that are used as access points for tanks or containers. However, these types of BLMs are not liquid tight and have a short useable life. For example, sliding gate BLMs tend to leak product under pressure. Moreover, because the sliding gate BLM's slide along seals, the sliding gate BLMs aggressively abrade the seals, shortening the useable life of the seals.
Accordingly there remains a need in the art for a BLM that easily opens and closes to manage a flow rate of product emptying out of a tank, does not impede the flow rate of product emptying out the tank, and provides a liquid tight seal under pressure of a vertical column of product contained in the tank.